Conventional digital cameras are configured to collect light bouncing off of the subject onto an image sensor through a lens. The image sensor immediately breaks down the light pattern received into a series of pixel values that are processed to form the end digital image of the subject.
Digital image technology is being used with increasing popularity leading to increasing production volumes. The increased production volumes are due not only to the increasing popularity of conventional digital cameras, but also due to miniature fixed-focused digital cameras being incorporated into various end products, such as mobile telephones (cellular telephones), personal digital assistants (PDA's), and other electronic devices.
However, during the manufacture of the digital camera modules, dust is often trapped within the camera module. Eventually, a portion of the trapped dust may impact the image sensor, more particularly, a die of the image sensor within the camera module and cause harm to the digital images produced. In particular, pixels created by the image sensor are extremely small, and any dust from the lens housing captured by the image sensor may cover one or more pixels of the entire image produced. In particular, a dust particle of approximately 5μ is large enough to cover an entire pixel of the image sensor die. By covering a pixel of the image sensor die, the end digital image is produced with a black dot where the covered pixel was to appear. As such, it is desirable to decrease the amount of dust particles contacting the image sensor die.
However, it is unlikely, or at least not cost efficient, to remove the presence of dust during the manufacturing process. For example, digital cameras are typically manufactured in a controlled environment classified under Federal Standard 209D as a class 1,000 environment. The clean room class 1,000 environment requires that less than 1,000 particles sized 0-5μ and less than 7 particles sized 5μ are found in each cubic foot of the clean room. Manufacturing a camera module within this environment will allow dust measuring between 0-5μ to be trapped inside of the camera module during manufacturing.
In addition, a camera module housing may be attached with screws to the image sensor and the lens or lens barrel is threadably attached to the camera module housing. The screw hole and barrel threads have relatively fine pitch and, as such, create small crevices that collect and essentially trap dust that cannot be effectively removed during manufacture. In particular, a blower cannot force air inside of the threads to remove the dust due at least in part to the small size of the threads. With this in mind, dust is left trapped within and between the camera module housing and the image sensor.
Subsequent movement and use of the camera module, in particular, subsequent twisting of the lens barrel, eventually releases the once trapped dust particles. In addition, camera housings are often comprised of a plastic material with glass filler particles. Movement and use of the camera module oftentimes pulls, grinds away, or removes a glass particle or a portion of the glass particle from the composite plastic material. The released glass particle contributes to the dust particles already present in the digital camera module. The released dust particles, whether the result of dust in the manufacturing process or of glass dust from the composite plastic material, often impact the image sensor resulting in undesirable blemishes of the digital image produced by the digital camera as described above.